I've used the wall worts to form charge my 5-cell NiMh batt's up to 2000mah no problem. It does take a while but works fine if you can wait. I now prefer to use my programmable charger and set it too C/10 (200 ma). Normally it won't peak charge at such a low rate. If it does I just re-start until it reaches the 16 hours. You can get the higher rate wall worts at Hangtime Hobbies I believe.